In the construction industry it is necessary to construct a building foundation on firm soil. When firm soil is unavailable, various pile systems are used to provide support from the hard pan soil that exists well below the soil surface to the foundation.
Generally, these pile systems use piles that can be directly drilled into the soil. Conventional piles have helical members that are shaped such that when the pile is rotated, it augers into the soil. The helical member also provides support for the pile and, under load, bears the load of the pile such that the pile is substantially fixed relative to the surrounding soil. The helix's diameter determines the amount of load that the pile will bear.
With higher loads and larger diameter helixes, the thickness of the helix becomes an issue. Generally, with higher diameter helixes it is necessary to increase the thickness of the helix in order to avoid flexing and eventual failure of helical members. Clearly, thicker helixes require more raw materials and, therefore, increased material cost. What is needed is a helix design that has the strength of a thicker helix, without the additional material cost.